Empty articles, such as bottles or other types of containers, are often conveyed as a singulated row of upright articles supported on a conveyor belt that moves the articles along a conveyor path.
Articles or groups of articles may fall or tip over while being conveyed and block further movement of upstream articles.
Friedrich, U.S. Pat. No. 3,610,399 discloses a conveyor having a pair of side fences that move articles partially off the conveyor belt to eject fallen articles off the conveyor belt. Using side fences to move articles partially of the conveyor belt cannot be used with some bottle shapes.